Electric switch



March 22, 1932. A. E ANGOLD ELECTRIC SWITCH Filed May 9, 1928 3Sheets-Sheet 1 A. E. ANGOLD l 850,703'

ELECTRIC SWITCH Filed May 9, 1928 3 Sheets-Sheet 2 FIG. 3

Mamh ZZ, 1932. A. E. ANGOLD 1,850,703

ELECTRIC SWITCH Filed May 9, 1928 3 Sheets-Sheet 3 I Jnz/pnfor,

ARTHUR ERNEST" ANGOLD, F BIRMINGHAM, ENGLAND, ASSIGITOR TOtTHE GENERALELECTRIC COMPANY, fLlMlTED, OF LONDON, ENGLAND Patentecl M ar. 22, 1932.

Parser FF-HGEI ELEornro swrrcn a neatmn'fileanay e, ieesysermi No. even49mm in Great Britain June 27,1927- This invention relates toelectricswitches, for example, circuit breakers adapted to be opened byio'rcestored during the closing thereof, and is particularly useful in connec-'tion with switches which in service carry relatively'large currents.One object of the inventionris to provide reliable contacts which willnot'become damaged by overheating, another objectEis to provide animproved contact comprisinga' plurality of separate elenientswhichindividually may readily be renewed or changed.

Iii the accompanying drawings, showing the switches with parts thereofomitted, Figure 1 is a sectional side elevation of one form of switch onthe line 1-1 of Figure 2; Figure 2 is a plan view of Figure 1; Figure asectional side elevation ofanother form of switch on the line 111-111 ofFigure 4; F igure 4'is a. plan view of Figure 3 with parts bro-kenaway'ywhilst Figure 5 "shows aside elevation'of a switch with a modifiedform of retaining member in section. large; 1, 3 and 5 parts of themoving switchcontact are shown in the positions occupied when "theswitch is closed by full lines, in the posi- 'tions occupied when theswitch being closed and has just reached the position in which themoving contact first bridges the fixed contacts by short chainlinesandin the positions occupied when the switch is open by long chain lines. r

In the drawings the switch is provided with fixed contacts 1 andQinadeof solid copper blocks insulatingly mounted upon the supporting member40 and adapted to be bridged I by a moving contact formed of copperblades 3 that 'are mounted on a supporting member in the form of a bar 4and that are acted upon by steel rod biassing springs 5. The bar 4 formspartof a: frame including two side members 7 between which the barextends and to which the bar is rigidly securedg Held to thesupportingmember 40 1s a bracket'52 formed with two arms-41'providedwith pivthe arms 41.

tension spring 45 to bias the inoving switch contact to the openposition.

'Pivoted at 47 to the arms 410i the bracket 52 iscan-operatinglever 48provided with a handle 51 and acting betweenthe end of the lever remotefrom the handle and pivots 46 formed at the ends of the bar 4 are thelinks 50., In the closed position ofthe switch the a toggle formed bythe lever 48 and link is slightly overset, but movement of the, lever ispreventedby a'stop 49 extending between If, however, the lever 48 isturned slightly in a counter clockwise direction away from the stop thespring 45 causes the toggle to collapse and rotates the side,

members 7 quickly in a clockwise direction to the open position. Ifthelever 48 isthen rotated in a clockwise; direction back to thepositlo-n in which it engages the stop 49 the S1Cl8Hl8-1Tlb61$ 7 areforced to rotate in a counterclockwise direction against the forcewiththe longitudinal teeth 8 the sides of which converge at an angle ofabout 60,

whilstthe ed es 9 of the blades 3 adjacent to "the fixed contacts aremade wedge shaped,

the angles of the wedge beingequal to the angles between opposite'facesof the teeth-8. The. wedge shaped edges 9 are blunt so that,

the edges do not extend to the roots ofthe teeth 8,-whilst the thicknessof blades 3 is. less than the pitch'of "teeth 8 and there aresubstantial air gaps 10 between the teeth] In Figs. 1 and 20f thedrawings the pivots 6 are constituted by parts of a spindle 11 extendingbetween the'arlns 41 of bracket 52 and rigidly attached to and extendingbetween the side members 7 is a cross piece 13. Secured to cross piece13 and projecting therefrom are the four springs 5 ofinv'erted L-shape,one for each blade3. The end of the short limb 14 of each springfiengages ina socket 15 formed inthe blade at a-point thereof about midwaybetween the fixed contacts 1 and'2, and thereby positions the bladelongitudinally on bar 4. A short distance above the sockets 15 theblades '3 are pierced by circular holes 16 considerablylargerthan theroundbar 4 which-1s threaded through the holes 16 and is secured rigidlyto the side members 7. The blades 3 are also provided at their lowerends with recesses 17 for avoiding interference of the spindle 11therewith. Moreover, the front part 18 of the upper edge of the crosspiece 13 acts as a stop with which,

during the later'part of the closing movement of the switch, the ends 19of the blades contact, thus limiting longitudinal movement of theblades'3 relatively to the side members 7, and causing the blades tomove lengthways relatively to the fixed contacts 1 and 2.

When the switch is opened by rotating the side members 7 about thepivotal axis 6, the springs press the blades 3 against the fixedcontacts ,1 and 2 until the bar 4 reaches the back edges of the holes 16in the blades, when the said member draws the blades away from the upperfixed contact 1, and the springs 5 acting on blades 3 at socket betweenthe bar 4 and contact 2 cause theblades 3 to pivot aboutthe bar 4, andmaintain the lower ends of the blades pressed against the bottom edge ofthe lower fixed contact 2, 'thusavoiding sparking thereat.

When the side members 7 are rotated in,

the opposite direction to close the switch, the wedge shaped contactfaces of the blades 3 after preliminary movement of the blades fullyengage between the teeth 8 of the lower fixed contact 2, and at the sametime engage between'the teeth 8 of the upper fixed contact 1, afterwhich the bar 4 moves away from the back edges of the holes 16 in theblades, the 5 rings 5 that are already strained are furtier strained,and the full force thereof is effective in pressing the blades againstthe upper and lower fixed contacts. During the closing of the switch,since the movement of cross piece 13 has a component in an upwarddirection, movement of the blades 3 occurs lengthways relatively to thefixed con .tacts 1 and 2, thereby giving a self cleaning action to theswitch contacts. The extent of the rubbing movement between the contentsdepends on the distance of cross piece 13 from the .axis of rotation 6thereof.

An alternative way of causingsuch lengthways movement of the bladesrelatively to the fixed contacts would be to form the holes '16 in theblades through which the bar 4 passes as sloping slots,.the arrangementbe ingsuch that the bar engages the upper ends of the slots when theswitch is open and the lower ends of the slots when the switch closed,thus causing the blades to slide upwards during the closing movement,and to rub on the fixed contacts 1 and 2.

c In Figures 3, 4 and 5 each blade 3 has riveted to its sides two plates24, formed with hooks 25, and lugs 26, that together with the hooks helpto position the springs 5. The upper end of each spring is for-med witha head 27 which engages a small recess 28 in the back edge of theassociated blade, whilst the bottom end of each spring is formed with atail 29 that bears against the said edge of the blade. Each springmoreover, slidingly fits between the plates 24 riveted to the associatedblade, and the greater part of the length of the spring is spaced fromthe back edge of the blade. The springs 5 near the mid points in thelengths thereof engage with the bar 4 formed with grooves 30 in whichthe springs find seatings, whereby the blades are positionedlongitudinally on bar 4.

The hooks 25 are provided with upper and lowerrsurfaces 31 and 32 whichloosely engage the upper and lower surfaces of the bar 4. In Figures 3and 4 the bar 4 is of square cross section, but the back surface 33 ofeach hook 25is not at right angles to the surfaces 31 and 32 thereof,and slopes backwards from the surfaces 31 to the surface 32. The blades3 are shown in short chain lines in the osition in which they have firstengage the contacts 1 and 2, but the bar 4 has not moved forward betweenthe surfaces 31 and 32 of hooks 25 further to compress :the sprin s5,and to press the wedge shaped edges of the blades 3 strongly between theteeth 8 of the fixed contacts 1 and 2. Figure 3 shows also that thegrooves 30 slope backwards from the lower to the upper surfaces of bar4, so that when the switch is closed the springs 5 contact only with thelower edges 34 of the grooves.

lVhen the bar 4 has been rotated around the axis 6 in a clockwisedirection as seen in Figure 3, from the fully closed position so.

that bar 4 slides between surfaces 31 and 32 of hooks 25 away from theblades 3 to the position shown in short chain lines, in which the strainonsprings 5 is partially relieved, and is then further rotated to openthe switch by moving the blades 3 from the fixed contact 1, the springs5 acting on the edges 34 of the grooves 30 cause the blades to tend topivot about the edge 35 of bar 4, with the result that the lowermostedges 36 of the wedge shaped faces of the blades 3 are maintained incontact with the sides of the teeth 8 of the fixed contact 2. Similarlythe edges 36 are maintained incontact with the fixed contact 2 whilstthe switch is being closed by rotating the blades 3 in acounterclockwise direction about the axis 6. The initial and finalmovements of bar 4, when the-switch 'is being opened and closedrespectively, and the bar slides between the surfaces 31 and 32 of hook25, cause the blades 3 to slide over the contacts 1 and 2, since the.bar has a component of movement in a direction parallel to thelongitudinal axes of the blades, which movement is transmitted to theblades by the bar-4 bearing on the surface 32 or on the surface 31.

Figure 5 shows parts of a switch similar to that of Figure 3 except thatthe bar 4is shaped as an angle iron suitable for use when 1'-Blades{ai1d springs; inav .atstrong barlis required .for. carrying arela- I tively 'large. number. of blades. 'In this 'in-' stance for the--.-purpose:of .maintaining'the Y :bladesfi in engagement Iwith theifixed .con-

pivot about-thepointSB'T of platesQAywhich points --engage the recess 38of thebar 45., 1 r:TAs;the ;bar'4;rotatesabout tllGfELXiS 6 in aclockwisedirectionas seenrin Figure 5, pres sure between the operativefaces of the blades blades 3 leaving; contact 1,: whilst thelowermost"edges 36* oftheblades are maintained -.in contact with thesides ofthe teeth Sof the fixedfcontactzina inannerfsimilar to thatalreadydescribed inconnection With Figures 311I1Cl-4, thesprings 5acting; onthe lowermost V 1 edges-3a of igrooves 30...; Clearly whenbar4 is rotated in a counterclockwise direction as Y seenziingFigure 5froin'.:thewopen position,-in

'- or'der to clo'se the switclnxtheblades 3 pivot about/thepoints37;untilthe operative faces .which; the points 37 disengage therecess 38 was the barf moves forwards in hook 25, and

H the springs 5 are vit'urtherstrained. '1'

-, The individual springs and bladesof Fig-, B

" supportthe strips b-utto allow liinited'movel ures3, 4 and '5 can:readily be removed or replaced without disturbing other parts of theinswitch, :forzif thehead 27 f a spring is drawn backwardsoutrofengagement with the :recess 28 of, the; corresponding blade thespringmay be pulled upwards, thus removingjit from between the plates24. After "an the spring has been removed the blade may beydisengagedfrom 'thebar't me'relyby slidging it-backwards', so that the-surface 32of shookisfree of the'adjacent under surface of the bar a, and-by thenlifting the blade.

-,,by converse operations; Y ffiglfthe contacts 1-and=2 andthe bar taremade sutficiently long the jcapacity of the k j switchxmayreadily-beincreased by adding more blades: The bar 4- may, for example,

-be' eXteIidedon the outer sides of 'the side fimemb ersziwhichsupportsthe bar andon which the bar is pivoted.

The blades?) may be associated with any suitable opening,- and ;;closingmechanism glwhich mayinclude catch 'geaiiforholding the circuit breakerclosed. Furthermore, the blade's r'nay be associatedwith auxiliary sparkingcontacts' of any: suitable kind, whilst 'theivariousparts of theswitch may be modified: inmany fdiiierent. ways gfor example, the.springs foractlnggfonthe blades in the typeofswitch shown inF igures 1and 2 may I *be formed-as plates or strips of steeltapere'd gfr'oin} theends Where they are secured to a tween the top and bottom contacts, andthe rubbing action that occurs on closing and opening the circuitbreakers helps t ensu-re close a circuit breaker is small, adequateproity of rigid strips ha ving edges adjacent and readily be replacedblades suchastwo blades. In operation the aforedescribed. circuitbreakers are normally prevented from becoming overheated since aircirculates freely around the blades, whilst the springs areii'emote fromthe-operative blade surfaces, so

that should the latter owingto overloadbe- Bxand contacts 1 fan'dq2iszmaintained, since, :-the springs 5, ar'e' initially s'trained toaprev .determinedextent, until the recess 38 engages f3 5 i 'the;points37 of platesQhafter Which,,upon

; further rotation ofthe bar, thejswitch opens,

come hot the springs remain relatively. cool and retain theirelasticity. The pressure of the springs, moreover, is shared evenlybenot only that the contactsurtaces are clean, 1

but that the blades are properlybedded against the fix'ed contacts whenthe circuit breakers are closed; Moreover, the voltage rlrops across thecontacts arefrelativelyj'low,

and although theamount of work required to vision'mayreadily be madeagainst wear ordistortion" of the fixecl rontacts or contact blaclessof'blades 3 and contacts 1 and 2 engage, after lclaimz 1. An electricswitch comprising a pluralsubstantially parallel toone another andconstituting contact surfaces,inea ns arranged to ment of the stripsrelatively thereto and biassing springs "separate from the stripsadapted togtransmit 'pressure through the strips to the said contactsurfaces when-the switch is "closed. q 4

'2. An electric switch comprising aphi- "ralit'yof rigid stripshaving"bevelle'd edges adjacent and substantially*parallel to oneanother and constituting contact surfaces, means arranged to supportthestrips but to when the switchfis closed. j

3. vAn electric switch comprising a plurality of rigid strips spacedapart from 'one -an-"lla other and having edges adjacent andsubstantiallyparallel to one another and constituting "contactsurfaces,means arranged to support the strips but to allow limited'movement'of J the strips 'relatively' thereto "and biass'ing lzofsprings'iseparate from the strips adapted'to act on" edges of thestripsreinotefroni' the said contact surfaces andtotransmitpressurethrough the, strips'tothe said contact I surfaces whenthe'switch isclosed. D j

4. An electric switch comprisinga plurali ty of rigid strips havingedges adjacent and substantially parallel to one another and con-:stitutingfcontact surfaces, means arranged to I support the strips buttoallow l mited,move-"-1lfl I fluent of "the strips relatively theretoand biassing sprin individually :associated with but separate rom .Ithevstrips 'andaadapted :to transmit pressurethrougli zthe stripsto thesaid contact surfaces when the switch .is closed. s

5. .An electric switch comprising a contact 'element,;a supportingmemberforsupporting .thecontact element, ahookshaped position- ,part providedon thecontact element-and ae easably engaging with the supporting:member and abarshaped spring which is xiwithdrawableia-ndacts at itsends on .thecon- -:tact element and between its ends on the supportingmember, the spring cooperating with the hook shaped positioning part in-;lock.ingthe contact element to the support- ,ingvmember. v

6. .An electric switchcomprising a contact 'elementin the form of astrip havingan edge which constitutes a contact surface, a sup- .portinmember for the contact element, a hooks aped positioning partprovided-onthe strip remote from the contact surface and iormed witha slot andreleasably engaging *w'mh thesupporting member, a bar shaped springwhich fits through the said slot and acts at its ends on the contactelement and between its ends on the supporting member and means .forlongitudinally positioning the spring which is withdrawable and whichcooperates "with the hook shaped positioning pantinlockingthercontact-element't-o the supmember. 7 e

7. An electric switch comprising a moving .bridgingcontactelement, asupportmgmembcr or supporting theicontact element, a positioning partprovided on the vcontact'ele- {Bent and .tormed with a pivotal edge andcooperating "with the supporting 'member which is'formed with onepivotal edgethat is ineng'a'gement with thepivotal-edge of theipositioning part duringiopening of the switch 7 and a second pivotaledge further :towards an ,end-ofthebridg' contact element than and.oppositely'dispos dd relatively .to the first 1votal-edge,. d a barshaped s r ng whic l is strained both when the swito is open and whentheswitch is closed and which acts intermediate its ends on the secondpivotal edge and at opposite sides of thesa id edge on the contactelement,

i 8. An electric switch comprising a moving bridging contact element asupporting memher for supporting the contact element, a positioning partprovided on the contact element and formed with a pivotal edge andcooperating with the supporting member which is formed with a pivotaledge that is in engagement with the pivotal edge of the I positioningpart during opening of the switch 3nd a'second pivotal edgefurthertowards an end of the bridging contact element than =andoppositely disposed relatively to the first pivotal edge, a bar shapedspring whichis blades spaced apart with edges rofthe :adjacent andsubstantially parallel tozone another, the said edgesbeing bevelled 'imdconstituting contact surfaces, a supporting strained both when the:switch is open and 'when'the switch is closed and which acts .in-

'termediate itszends on thesecond pivotal e andiat opposite sides ofthegsaid edge on e contact element, and a pivot spaced when the switchclosed 'to one side of the supporting member which is adapted to rotateabout said pivot.

19. An electric switch comprisin it 'movin bridging contact including ap are its member for supportingthe bridging contact, hook shapedpositioning ipazrts provided on the blades and formedisl'ots and withpivotal edges and releasably enga the supporting member which is formeda one pivotal edge that is in engagement with aha pivotal edges of thepositioning parts during opening of'the switch'and a second pi v- 'otaledge further towards (an end of the bugsing contact than and-oppositelydisposed atively to'the first pivotal edge, a m of bar shaped springseach of which is willidrawable and is strained when the switch is openand is further strained when thesavitch is closed and passes through -.aslot in a positioning part and acts intermediate its ends on the secondpivotal edge and atopposite sides ofthe'said edge onablade'uemote fromthe bevel-led edge thereof :and cooperates with the hook shapedosition'ing part of the blade inloc king'the ladeto timingportingmember, means for longitud positioning the springs, and a pivot spacedwhen the switch is closed to one side of the supporting member which is"adapted to rotate about the said pivot.

10. An electric switch compris' V 5a moving bridging contact including:a lade In edge of which constitutes a contact surface, supporting meansarranged to support the blade but 'to allow limited movement of theblade relatively thereto and includingm pivot, and a biassing springarranged to act on the blade between the ivot and an end of the rlimited movement of the blades relatively v thereto and includingpivotal means, andbar shaped biassing springs arranged respectively toact on the edges of the blades remote from the said contacttsurfacesbetween the pivotal means vand an end of the c0ntact,'the springs beingstrained when the switch is open and further strained when'the' switchis closed and being adepted t0 trans= mit pressure through the blades tothe con tact surfaces.

In testimony whereof I aflix my signature.

ARTHUR ERNEST 'ANGOLD.

